Flexible protection layer for body protecting products

ABSTRACT

Method for producing a flexible protection layer which can be incorporated in different body protecting products in order to prevent injuries caused by penetrating objects, such as nails, pointed weapons and the like. According to the method polymer fibres having a high breaking point are embedded in a hardenable binding material so that the binding material surrounds the fibres and upon hardening fixes the fibres in their positions. The method is characterized in that the fibres are embedded in the binding material in a mutually unarranged order, preferably felted together. The invention also relates to a flexible protection layer produced in accordance with the method and which can be incorporated in different body protecting products.

FIELD OF THE INVENTION

[0001] The present invention relates to a method of producing a flexible protective layer which can form part of various body-protecting products in order to prevent injuries caused by penetrating objects, such as nails, pointed weapons and the like, in which polymer fibers with high ultimate strength are embedded in a hardenable binder, so that the latter surrounds the fibers and, after hardening, fixes the fibers in the positions in which they are located.

[0002] The invention also relates to a flexible protective layer which can form can form part of various body-protecting products, and also footwear and articles of protective clothing with such protective layers.

BACKGROUND OF THE INVENTION

[0003] In many situations, there is a need for protective layers which can be integrated into various body-protecting products in order to prevent injuries caused by penetrating objects such as nails, pointed weapons and the like. One area where a great need exists f or protection against penetrating nails is footwear for people who work on construction sites, where inter alia construction timber with projecting nails is found. Treading on a nail can give rise to serious foot injuries and infections.

[0004] It has long been known to use inserts made of steel or metal in footwear for construction workers. Such metal inserts can provide good protection but have certain disadvantages. Among other things, they contribute to making he shoe relatively rigid and stiff. This prevents normal bending of the foot and impairs the sense of feeling against the ground, which can increase the risk of inter alia falling and slipping accidents.

[0005] In order to overcome some of these problems, U.S. Pat. No. 1,701,611 describes footwear with a flexible metal insert which comprises a woven metal wire fabric. However, the use of metal also results in other disadvantages, as metals are usually good conductors of both heat and electricity. Shoes with metal inserts therefore impair the possibility of keeping the foot warm in a cold climate and can, on account of their conductive capacity, constitute risks in some workplaces and for certain occupational groups such as, for example, electricians.

[0006] In order to eliminate problems associated with using metal, the use of synthetic fiber material embedded in a shoe sole has previously been proposed. In this connection, the fibers are woven into a fabric, and one or more layers of such a fabric can then be molded integrally in a shoe sole, so that the material of the shoe sole completely impregnates the woven layers. An example of a protective boot with such a sole is described in U.S. Pat. No. 5,979,081.

[0007] WO 99/13744 describes a variant of a protective boot with layers of synthetic fiber fabric integrated into the sole. In this case, the fibrous fabric is not impregnated with binder in the sole but can, for example, be fitted in a pocket formed between the inner and the outer sole of footwear.

[0008] It is common to all known protective layers using synthetic fibers with high ultimate strength that the fibers are applied in the form of a woven fabric or the like, that is to say in a structure in which the fibers are in some way arranged in a predetermined pattern relative to one another. Testing has nevertheless shown that a nail, for example, is capable of “finding its way through” any arranged fibrous structure, even if the latter consists of a very tight weave. In order to prevent this, an impractical number and thickness of woven layers would be required. This would make the shoe clumsy, and increase its weight and the consumption of expensive fibrous material.

THE OBJECT OF THE INVENTION

[0009] A main object of the present invention is to provide a method of producing a flexible protective layer which can, for example, be used in footwear as anti-nail protection, affords improved protection and can consist of relatively thin and light layers.

[0010] The invention is based on the insight that this aim can be achieved by using fibers made of a synthetic material with high ultimate strength, which fibers are not woven or otherwise joined together so that they form a regular structure before they are embedded in the binder.

[0011] In this connection, according to the present invention, the particularly characteristic feature of a method of the type indicated in the first paragraph is that the fibers are embedded in the binder in an unarranged state in relation to one another.

[0012] The protective layer will therefore consist of a binder layer reinforced with fibers which are located close together and are fixed in random positions relative to one another. Such a layer with randomly oriented fibers has been found to have very great resistance to penetration and to constitute extraordinarily good protection against penetrating objects such as nails, pointed weapons and the like.

[0013] It is preferable for the fibers to be felted together to form a handleable product before they are embedded in the binder. This facilitates handling of the fibers and thus the manufacture of the protective layer without the fibers having to be structured as in a woven fabric or the like.

[0014] In an especially preferred method according to the invention, use is made of a high-molecular polyethylene fiber sold under the trademark DYNEEMA® which, as a consequence of its properties, inter alia a very high ultimate strength and great rigidity, has been found to afford extraordinarily good protection against penetration when, for example, fibers made of this material are molded integrally, in an unarranged state, in a shoe sole, suitably made of polyurethane.

[0015] Other features of a method according to the invention and a protective layer manufactured by means of the method and also products provided with such protective layers emerge from the following patent claims.

[0016] The invention will be described in greater detail below with reference to the illustrative embodiment shown by way of example in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

[0017]FIG. 1 illustrates a shoe made with a sole with a protective layer according to the invention.

[0018]FIG. 2 is a cross section through the shoe according to FIG. 1.

[0019]FIG. 3 is an enlarged part of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020]FIGS. 1 and 2 show a protective shoe according to the invention with an upper part 1 which, if desired, can be made with a protective cap (not shown) of conventional type. Reference number 2 indicates an outsole, suitably made of polyurethane, and reference number 3 an insole made of a comfort-improving material.

[0021] The designation 4 indicates a layer for protection against penetration by nails or other sharp, penetrating objects when trodden on. This layer consists of a fibrous material which is molded integrally in the polyurethane material of the outsole 2, so that the fibers in the layer 4 maintain the relative positions they adopted in connection with the molding process. The fibrous material is therefore completely impregnated with the polyurethane material of the sole, so that this material completely surrounds the fibers and fixes their directions relative to one another, as can be seen more clearly from FIG. 3.

[0022] According to the invention, the fibers in the layer 4 are arranged randomly in relation to one another, so that they do not form an arranged fibrous structure like a woven fabric or equivalent.

[0023] In order to produce a handleable product made of such randomly oriented fibers, which can be inserted into the mold in which the outsole is molded during shoe manufacture, the fibers can be felted together. Felting means that the fibers become hooked together and attached to one another without forming a regular pattern. Such a felted or tangled layer can, even if it is thin, be handled as a unit during the procedure for manufacturing the sole. Other methods of holding the fibers together without them being structured but which facilitate their handling can also be used. The important feature is that the fibers are in “chaos”, that is to say in an entirely unarranged state.

[0024] The fibers can, for example, be felted together to form layers with a weight per unit area of roughly 500 g/m2. During manufacture of the sole, it is then suitable for two layers to be arranged one on another. Depending on the thickness, it is also possible to use a single layer or more than two layers.

[0025] According to the invention, it is preferable to use fibers made of a high-molecular polyethylene material which is marketed under the tradename DYNEEMA®. Other fibrous materials with equivalent properties can also be used. The invention also includes the use of new fibers with improved values which may be developed in the future.

[0026] What makes fibers made of DYNEEMA® especially suitable is inter alia their high ultimate strength and great rigidity, which properties together afford very good protection against penetrating objects. A suitable fiber quality is DETEX 2.2.

[0027] According to the above, the invention aims primarily to provide a means of protection against penetrating objects of the type indicated above, such as nails, pointed weapons and the like, which have a relatively low speed in comparison with projectiles, such as bullets.

[0028] The invention has been described above in connection with the protective shoe shown in the figures, in which a protective layer is molded integrally in the outsole. As an alternative to this, the protective layer can also be molded integrally in a loose insole or in the fixed insole.

[0029] The protective layer according to the invention is also suitable for producing, for example, flexible protective jackets and protective trousers which provide protection against, for example, stabbing with a knife. In this context, the possibility of producing a flexible protective layer is of the greatest importance. This is achieved owing to the fact that a protective layer according to the invention can be made thin and contains flexible fibers. The binder is then selected depending on application and can consist of, apart from polyurethane, other polymeric elastomers. 

1. A method of producing a flexible anti-nail protective layer for footwear intended to prevent injuries caused by penetrating objects, such as nails and the like, in which polymer fibers with high ultimate strength are embedded in a hardenable binder, so that the latter surrounds the fibers and, after hardening, fixes the fibers in the positions in which they are located, characterized in that, in a first step, the, fibers are treated so that they form a handleable product, in which the fibers are present in an unarranged state in relation to one another, and in that, in a second step, this product is embedded in the binder which is shaped to form a sole of the footwear.
 2. The method as claimed in claim 1, characterized in that the fibers are felted together to form a handleable product which is embedded in the binder.
 3. The method as claimed in claim 1 or 2, characterized in that a high-molecular polyethylene fiber is used as the fiber.
 4. The method as claimed in any one of claims 1-3, characterized in that the fibers are molded integrally in a layer of the outsole of the footwear, which layer forms said protective layer.
 5. The method as claimed in claim 4, characterized in that the fibers are molded integrally in an outsole made of polyurethane.
 6. The method as claimed in any one of claims 1-3, characterized in that the fibers are embedded in a binder which is shaped to form a fixed insole or a loose insole.
 7. The method as claimed in any one of claims 2-6, characterized in that one or more fibrous layers produced by felting fibers together is or are embedded in the binder.
 8. A flexible anti-nail protective layer for footwear intended to prevent injuries caused by penetrating objects, such as nails and the like, which comprises polymer fibers with high ultimate strength embedded in a hardenable binder which surrounds the fibers and, in the hardened state, fixes the fibers in their positions relative to one another, characterized in that the fibers are pretreated to form a handleable product, in which the fibers are present in an unarranged state in relation to one another, and in that the fibers are embedded in the binder in the form of a sole of the footwear.
 9. The protective layer as claimed in claim 8, characterized in that the fibers form part of a handleable product which is obtained by felting and is embedded in the binder.
 10. The protective layer as claimed in claim 8 or 9, characterized in that the fibers comprise a high-molecular polyethylene fiber.
 11. The protective layer as claimed in any one of claims 8-10, characterized in that the fibers are molded integrally in a layer of the outsole (2) of the footwear, which layer forms said protective layer (4).
 12. The protective layer as claimed in claim 11, characterized in that the fibers are molded integrally in an outsole (2) made of polyurethane.
 13. The protective layer as claimed in any one of claims 8-10, characterized in that the fibers are molded integrally in a binder shaped to form a fixed insole or a loose insole.
 14. Footwear with anti-nail protection, characterized in that it comprises a sole (2) with a flexible protective layer (4) as claimed in any one of claims 8-13. 